Name a post-construction BMP that reduces peak runoff and improves water quality.

Name a post-construction BMP that reduces peak runoff and improves water quality.

• A. Vegetated swales/bioretention areas
• B. Erosion control blankets
• C. Riprap channel protection
• D. Concrete curb and gutter

Answer: (A)

Post-construction BMPs that slow and treat runoff use vegetation and soil to store, infiltrate, and filter water, which lowers the amount and speed of water leaving the site while removing pollutants. Vegetated swales and bioretention areas accomplish this by creating shallow, planted channels or depressions filled with soil media. As stormwater moves through them, the water is detained and infiltrates into the ground, and pollutants are removed through physical filtration, adsorption to the media, plant uptake, and microbial processes. This combination reduces the peak runoff during storms and improves water quality before the water exits the site. Other options aren’t designed for ongoing pollutant removal or peak reduction after construction. Erosion control blankets are typically temporary stabilization measures used during construction. Riprap channel protection protects against erosion but doesn’t filter pollutants or significantly slow and treat the runoff. Concrete curb and gutter convey water quickly with minimal treatment, so they don’t provide the water-quality benefits described here.

Post-construction BMPs that slow and treat runoff use vegetation and soil to store, infiltrate, and filter water, which lowers the amount and speed of water leaving the site while removing pollutants. Vegetated swales and bioretention areas accomplish this by creating shallow, planted channels or depressions filled with soil media. As stormwater moves through them, the water is detained and infiltrates into the ground, and pollutants are removed through physical filtration, adsorption to the media, plant uptake, and microbial processes. This combination reduces the peak runoff during storms and improves water quality before the water exits the site.

Other options aren’t designed for ongoing pollutant removal or peak reduction after construction. Erosion control blankets are typically temporary stabilization measures used during construction. Riprap channel protection protects against erosion but doesn’t filter pollutants or significantly slow and treat the runoff. Concrete curb and gutter convey water quickly with minimal treatment, so they don’t provide the water-quality benefits described here.